I upgraded the OS on my iPad and MacBook Pro today. I also set up the “new” two factor system. I hadn’t set it up with the old system when I set up two factor on many other accounts.
Setup was easy as described here. I added both my home and cell numbers. I like that you can choose whether to receive a text or phone call with the code. A code was sent to or called on each phone to verify. Since I set this up from my Mac, it became a trusted device. My iPad is recognized as logged in, but not trusted so the code only appears on my Mac.
I then signed in to my apple account in Safari to try to set it up as trusted. On my Mac, the six digit verification code automatically popped up. Minor bug, it was a window that went to the background when I tabbed away and I couldn’t find it when command+tab to switched. I had to drag my browser window out of the way to get it back. When I went to look at iCloud > username > devices on my iPad, I again got the location/verification code pop up on my computer. More convenient this time since it was a different device. I like that it shows the location of the device that wants the code.
I also got an email saying I turned on two factor and that I can opt out by clicking the link for a limited time. I like that the link expires to reduce the attack surface. Of course, I can always opt out through actually logging into my account.
The only problem is that I can’t figure out how to make my iOS 9.1 iPad a trusted device. The option just isn’t there under iCloud > username > password and security.